In a far distant galaxy, the Twelve Colonies of Man are at war with the Cylons, a race of deadly robots bent on the total extermination of humanity. When the Cylons propose a peace treaty the Colonial high council sees an opportunity to end the conflict; but the pact is merely a trick, and a huge armada of Cylon raiders attacks the unsuspecting Colonial empire, killing millions of citizens in a terrible onslaught. As the Colonial fleet is decimated by the merciless Cylon forces, only one Battlestar, the Galactica, is able to escape. Lead by Commander Adama, the vessel flees the solar system leading a rag-tag fleet of two-hundred-and-twenty military and civilian spaceships – all that remains of the human race. However, Adama recalls a legend of a lost, Thirteenth Colony situated on a remote planet known as Earth; he decides to take the Galactica and its fleet in search of this haven, even though the journey will be long and arduous, and the surviving humans will have to deal with food shortages, cramped conditions and low morale. En route, the Galactica stops off at the ore-mining world of Carillon for refuelling; Captain Apollo, Lieutenant Starbuck and Lieutenant Boomer lead a scouting party down to the planet surface, where they discover a huge casino. Investigating the popular tourist resort they soon discover that all is not what it seems, and it is not long before they come face-to-face with a carnivorous insect race known as the Ovions, and their allies – the Cylons…

*This story was originally shown as a triple-length episode; for subsequent repeats, the story was split into three parts

*In some parts of North America the series premiere was interrupted for over an hour due to the signing of the Israel / Egypt peace accord by Israeli Premier Menachem Begin and Egyptian President Anwar Sadat, which was overseen by U.S. President Jimmy Carter

*This TV movie was also released theatrically in cinemas in 1978; apart from a running time of 125 minutes, the most notable difference was that in the theatrical version, Baltar was executed by the Cylons